The seven internalizing disorders included match the set of internalizing disorders used in the seminal work on the empirical structure of psychopathology that inspired the present project (i.e., Krueger, 1999). However, the absence of disorders such as PTSD and OCD in earlier studies may reflect their absence in several large epidemiological datasets (including NESARC, wave 1 in which the present work was conducted) more than any theoretical or substantive considerations. With that said, a limited amount of work suggests that PTSD may be distinct from other internalizing disorders in its association with latent internalizing and externalizing factors (Wolf et al., 2010). Thus, we leave it to future research to determine how internalizing disorders not included in the present work would fit into the structural models we tested. Future studies examining such issues would have the potential to extend the findings presented here in important ways.
